Studies on heterosis and inbreeding depression for yield and phsiological traits in groundnut (Arachis hypogaea l.)

Estimates of heterosis and inbreeding depression were obtained for 28 crosses. For pod yield per plant, the maximum better parent and mid parent heterosis was recorded in the cross TCGS-584× K-1375 closely followed by K-1375× TCGS-647 and ICGV-99029 x K-1375. Kernel yield per plant, the range of heterosis was observed-11.10% (TIR-25 x ICGV-91114) to 57.61% (K-1375 x TCGS-647), -14.18% (TIR-25 x ICGV-91114) to 55.85% (K-1375 x TCGS-647) and-21.57% (TCGS-584 x TCGS-647) to 23.09% (TPT-4 x TIR-25) over mid parent, better parent and standard parent respectively. For the important of moisture stress tolerant characters viz., for specific leaf area, highest negative heterosis was recorded by TCGS-584 x JL-220 over mid parent (−23.12%), better parent (−25.14%) and standard parent (−34.95%). For leaf area index, TCGS 584 x JL-220 (−22.36%) over mid parent, TIR-25 x JL-220 (−33.81%) over better parent and ICGV-99029 x K-1375 (−24.14%) over standard parent for transpiration rate, ICGV-91114 x ICGV-99029 over mid parent (−26.33%) and better parent (−32.21%) and TPT-4 x TIR-25 over standard parent (−15.06%) hybrid showed desired significant heterosis. It was evident that ICGV-91114 x TCGS-584 for SPAD chlorophyll meter reading, TIR-25 x TCGS-584 for photosynthetic rate, ICGV-91114 x ICGV-99209 for water use efficiency and TIR-25 x JL-220 for harvest index and as many as twenty two crosses for yield displayed higher levels of heterosis also had high inbreeding depression.